Our annual game plan is to announce a few (usually between 2 and 6) celebrities leading up to the holiday season following the expo to spur Christmas sales. Then we take a step back and really look at what direction we want to take the lineup and start contacting agents the first of the year.
As contracts are finalized (usually a 30-60 day process) we start announcing our lineup for the coming year. Because we have to allow so much time for the celebrities to check their schedules for such things as other appearances, filming schedules, and even family events we usually start seeing the results in March and April and then on into early summer.
Once we have a good idea who is not going to be able to appear from that initial round of contacts, we then reach out again on a smaller, more focused scale to fill in our lineup. This is why we are more often than not announcing celebrities right up to the week of the convention.